docs: def get_protein_id_list(df, level=0):
      """
      Return a complete list of shortform IDs from a DataFrame
  
      Extract all protein IDs from a dataframe from multiple rows containing
      protein IDs in MaxQuant output format: e.g. P07830;P63267;Q54A44;P63268
  
      Long names (containing species information) are eliminated (split on ' ') and
      isoforms are removed (split on '_').
  
      :param df: DataFrame
      :type df: pandas.DataFrame
      :param level: Level of DataFrame index to extract IDs from
      :type level: int or str
      :return: list of string ids
      """
      protein_list = []
      for s in df.index.get_level_values(level):
          protein_list.extend( get_protein_ids(s) )
  
      return list(set(protein_list))